This is a note to let you know that I've just added the patch titled
mfd: stmpe: Fix RESET regression on STMPE2401
to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mfd-stmpe-fix-reset-regression-on-stmpe2401.patch
and it can be found in the queue-4.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f40584200bc4af7aa4399635b9ac213c62a13ae7 Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@xxxxxxxxxx>
Date: Tue, 1 Nov 2016 10:22:53 +0100
Subject: mfd: stmpe: Fix RESET regression on STMPE2401
From: Linus Walleij <linus.walleij@xxxxxxxxxx>
commit f40584200bc4af7aa4399635b9ac213c62a13ae7 upstream.
Since commit c4dd1ba355aae2bc3d1213da6c66c53e3c31e028
("mfd: stmpe: Add reset support for all STMPE variant")
we're resetting the STMPE expanders before use.
This caused a regression on the STMP2401 on the Nomadik
NHK8815:
stmpe-i2c 0-0043: stmpe2401 detected, chip id: 0x101
nmk-i2c 101f8000.i2c0: write to slave 0x43 timed out
nmk-i2c 101f8000.i2c0: no ack received after address transmission
stmpe-i2c 0-0044: stmpe2401 detected, chip id: 0x101
nmk-i2c 101f8000.i2c0: write to slave 0x44 timed out
nmk-i2c 101f8000.i2c0: no ack received after address transmission
It turns out that we start to poll for the reset bit to
go low again too quickly: the STMPE2401 is not yet online and
ready to be asked for the status of the RESET bit.
By introducing a 10ms delay before starting to hammer
the register for information, we get back to normal:
stmpe-i2c 0-0043: stmpe2401 detected, chip id: 0x101
stmpe-i2c 0-0044: stmpe2401 detected, chip id: 0x101
Cc: Amelie Delaunay <amelie.delaunay@xxxxxx>
Fixes: c4dd1ba355aa ("mfd: stmpe: Add reset support for all STMPE variant")
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Acked-by: Patrice Chotard <patrice.chotard@xxxxxx>
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/mfd/stmpe.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/mfd/stmpe.c
+++ b/drivers/mfd/stmpe.c
@@ -761,6 +761,8 @@ static int stmpe1801_reset(struct stmpe
if (ret < 0)
return ret;
+ msleep(10);
+
timeout = jiffies + msecs_to_jiffies(100);
while (time_before(jiffies, timeout)) {
ret = __stmpe_reg_read(stmpe, STMPE1801_REG_SYS_CTRL);
Patches currently in stable-queue which might be from linus.walleij@xxxxxxxxxx are
queue-4.8/gpio-do-not-double-check-direction-on-sleeping-chips.patch
queue-4.8/mfd-stmpe-fix-reset-regression-on-stmpe2401.patch
queue-4.8/i2c-mux-fix-up-dependencies.patch
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